Subversion Repositories QNX 8.QNX8 LLVM/Clang compiler suite

//===- MCSectionCOFF.h - COFF Machine Code Sections -------------*- C++ -*-===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

//

// This file declares the MCSectionCOFF class.

//

//===----------------------------------------------------------------------===//

#ifndef LLVM_MC_MCSECTIONCOFF_H

#define LLVM_MC_MCSECTIONCOFF_H

#include "llvm/ADT/StringRef.h"

#include "llvm/MC/MCSection.h"

#include "llvm/MC/SectionKind.h"

#include <cassert>

namespace llvm {

class MCSymbol;

/// This represents a section on Windows

class MCSectionCOFF final : public MCSection {

  // FIXME: The following fields should not be mutable, but are for now so the

  // asm parser can honor the .linkonce directive.

  /// This is the Characteristics field of a section, drawn from the enums

  /// below.

  mutable unsigned Characteristics;

  /// The unique IDs used with the .pdata and .xdata sections created internally

  /// by the assembler. This ID is used to ensure that for every .text section,

  /// there is exactly one .pdata and one .xdata section, which is required by

  /// the Microsoft incremental linker. This data is mutable because this ID is

  /// not notionally part of the section.

  mutable unsigned WinCFISectionID = ~0U;

  /// The COMDAT symbol of this section. Only valid if this is a COMDAT section.

  /// Two COMDAT sections are merged if they have the same COMDAT symbol.

  MCSymbol *COMDATSymbol;

  /// This is the Selection field for the section symbol, if it is a COMDAT

  /// section (Characteristics & IMAGE_SCN_LNK_COMDAT) != 0

  mutable int Selection;

private:

  friend class MCContext;

  // The storage of Name is owned by MCContext's COFFUniquingMap.

  MCSectionCOFF(StringRef Name, unsigned Characteristics,

                MCSymbol *COMDATSymbol, int Selection, SectionKind K,

                MCSymbol *Begin)

      : MCSection(SV_COFF, Name, K, Begin), Characteristics(Characteristics),

        COMDATSymbol(COMDATSymbol), Selection(Selection) {

    assert((Characteristics & 0x00F00000) == 0 &&

           "alignment must not be set upon section creation");

  }

public:

  /// Decides whether a '.section' directive should be printed before the

  /// section name

  bool shouldOmitSectionDirective(StringRef Name, const MCAsmInfo &MAI) const;

  unsigned getCharacteristics() const { return Characteristics; }

  MCSymbol *getCOMDATSymbol() const { return COMDATSymbol; }

  int getSelection() const { return Selection; }

  void setSelection(int Selection) const;

  void printSwitchToSection(const MCAsmInfo &MAI, const Triple &T,

                            raw_ostream &OS,

                            const MCExpr *Subsection) const override;

  bool useCodeAlign() const override;

  bool isVirtualSection() const override;

  StringRef getVirtualSectionKind() const override;

  unsigned getOrAssignWinCFISectionID(unsigned *NextID) const {

    if (WinCFISectionID == ~0U)

      WinCFISectionID = (*NextID)++;

    return WinCFISectionID;

  }

  static bool isImplicitlyDiscardable(StringRef Name) {

    return Name.startswith(".debug");

  }

  static bool classof(const MCSection *S) { return S->getVariant() == SV_COFF; }

};

} // end namespace llvm

#endif // LLVM_MC_MCSECTIONCOFF_H